Adam Clarke on John 10:5

And a stranger will they not follow - That is, a man who, pretending to be a shepherd of the flock of God, is a stranger to that salvation which he professes to preach. His mode of preaching soon proves, to those whose hearts are acquainted with the truths of God, that he is a stranger to them; and therefore, knowing him to have got into the fold in an improper way, they consider him a thief, a robber, and a murderer; and who can blame them if they wholly desert his ministry? There are preachers of this kind among all classes.